Hsp27 enhances recovery of splicing as well as rephosphorylation of SRp38 after heat shock.
Mol Biol Cell
; 17(2): 886-94, 2006 Feb.
Article
em En
| MEDLINE
| ID: mdl-16339078
ABSTRACT
A heat stress causes a rapid inhibition of splicing. Exogenous expression of Hsp27 did not prevent that inhibition but enhanced the recovery of splicing afterward. Another small heat shock protein, alphaB-crystallin, had no effect. Hsp27, but not alphaB-crystallin, also hastened rephosphorylation of SRp38-dephosphorylated a potent inhibitor of splicing-after a heat shock, although it did not prevent dephosphorylation by a heat shock. The effect of Hsp27 on rephosphorylation of SRp38 required phosphorylatable Hsp27. A Hsp90 client protein was required for the effect of Hsp27 on recovery of spicing and on rephosphorylation of SRp38. Raising the Hsp70 level by either a pre-heat shock or by exogenous expression had no effect on either dephosphorylation of SRp38 during heat shock or rephosphorylation after heat shock. The phosphatase inhibitor calyculin A prevented dephosphorylation of SRp38 during a heat shock and caused complete rephosphorylation of SRp38 after a heat shock, indicating that cells recovering from a heat shock are not deficient in kinase activity. Together our data show that the activity of Hsp27 in restoring splicing is not due to a general thermoprotective effect of Hsp27, but that Hsp27 is an active participant in the (de)phosphorylation cascade controlling the activity of the splicing regulator SRp38.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Repressoras
/
Splicing de RNA
/
Proteínas de Ligação a RNA
/
Proteínas de Ciclo Celular
/
Proteínas de Choque Térmico
/
Proteínas de Neoplasias
Limite:
Humans
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article